The main trust of this program is to provide research training for a minimum of 3 years in pulmonary biology for M.D. and Ph.D. candidates at the postdoctoral level. The goal is to provide research training for young investigators who will pursue academic research careers in biomedical sciences as they relate to the respiratory system. The research trainee, with guidance from program directors, will select a well-defined topic in the program. The trainee will then work with a senior research mentor for the duration of training. An outstanding faculty of IS (both MD's and PhD's ) is drawn from basic science and clinical departments. The primary focus of the training is in the Pulmonary and Critical Care Unit of the Department of Medicine at Massachusetts General Hospital. Three specialized research groups, cellular and molecular biology, occupational medicine and molecular biology and positron emission tomography, provide each trainee a more cloistered and focused environment depending on their selected research project. The senior mentor will closely monitor the trainee's progress, with period review by program directors. The entire program will be reviewed annually by an outside scientific advisory committee. Specific courses in Biology of the Respiratory Tract, Epidemiology and Biostatistics, Ethics and Clinical Effectiveness will be offered as part of the training. An interactive, multidisciplinary internationally recognized faculty provides a strong and exciting intellectual environment for research. At the conclusion of the training period, each trainee will have become adept and have appropriate expertise in one of the fields identified above and will be able to continue in an academic environment in biomedical research.